Emulsions for lignocellulosic products, methods of their manufacture, improved lignocellulosic products and methods for their manufacuture

ABSTRACT

Emulsions are provided which are useful in imparting water-resistance to lignocellulosic products. In one embodiment, the emulsions contain a nonsaponifiable wax, a saponified wax, an alkyl phenol component, a dispersant/surfactant such as a salt of polynaphthalenesulfonic acid, and a carboxymethylcellulose. Such emulsions may be added to hot, even boiling, water without the emulsion separating or curdling. Various embodiments are stable for extended periods of time when stored at room temperature, do not require the addition of a preservative biocide to avoid contributing to biodegradation in a lignocellulosic product. The emulsions are pourable liquids at room temperature. Optionally, the emulsions may be added to lignocellulosic products with a preservative to inhibit the preservative from leaching out.

FIELD OF THE INVENTION

The present invention relates to emulsions useful in improvinglignocellulosic composite products and wood. The present inventionfurther relates to a method of making the emulsions.

BACKGROUND OF THE INVENTION

The panel board industry, includes, but is not limited to, plywood, OSB(Oriented Strand Board) (commonly referred to as flake or wafer board),medium density fiber board, particleboard, and other products,inclusively referred to herein as lignocellulosic composite products. Ineach of these composite products and in lumber (the wood of trees cutand prepared for use as building material) (collectively referred toherein as “lignocellulosic products”) it is desirable to control thewater absorption or “uptake” and swelling, both of which havedetrimental affect on the utility of the product. For example, inplywood used for floor underlay, swelling causes buckling or creep inthe final wood or tile overlay. Similar problems occur with swelled OSBused as a roofing member applied to areas which will experiencemoisture. These composite board panels, like wood and otherlignocellulosic products, are also known to deteriorate on the job sitedue to open storage, as a result of water uptake, which leads tobiological degradation resulting from the growth of, and infestation by,bacteria, fungi, and insects.

Lignocellulosic composite products are conventionally manufactured byhot pressing lignocellulosic materials with wax and thermosetting resin.This is referred to as a conventional bonding process. The wax is asizing agent to improve the water resistance of the composite. The resinis a bonding agent that holds the materials comprising the compositetogether, thus forming them into a unitary shape. Resoles are commonlyused as the binding resin for lignocellulosic composite products.

In the conventional hot press method of manufacture of lignocellulosiccomposite products, a lignocellulosic material is combined with aphenolic resin and other components in a blender or mixer. The blend ormixture that results is pressed, typically under pressures aboveatmospheric and temperatures greater than room temperature, to producethe composite. Lignocellulosic materials used in the production of matsmay be selected from the group consisting of wood fiber, wood flake,wood strands, wood chips and wood particles, and mixtures thereof. Thelignocellulosic materials listed here are referred to in the art as woodfurnish. However, it is well known that other wood furnish, such asstraw, bagasse, wood bark, recycled wood fiber, recycled paper fiber,and mixtures thereof, may also be used. The wood furnish, once blendedor mixed with the phenolic resin, is then formed onto a support materialto make a pre-form in the approximate shape of the finished good. Thepre-form is then placed on a caul plater in a hot press where thefinished good is produced by applying pressures above atmospheric andtemperatures greater than room temperature. The elevated temperaturesand pressures cause the phenolic resin to polymerize, thus binding thepre-form into a unitary finished good. The hot press method is furtherdescribed in U.S. Pat. No. 4,433,120 to Shui-Tung Chiu.

Lignocellulosic composite products primarily find use in construction orfabrication. These products may be used in building construction or anyfabrication where wood is traditionally used. The poor dimensionalstability of state-of-the-art lignocellulosic composite products affectstheir mechanical properties and reduces their load carrying ability.Another result of poor dimensional stability is unevenness of roof andfloor underlayments, and of building siding. Two methods have beenprincipally suggested as means to produce dimensionally stablelignocellulosic composite products. However, both of these methods haveproven to be too costly to be used in practice. The first method isreferred to as Bulking Treatment. In this method, lignocellulosicmaterials are impregnated with water-soluble polymers such aspolyethylene glycol or impregnated with a low molecular weight resinsuch as phenol-formaldehyde, or with vinyl monomers and polymerized insitu. The second method is referred to as Chemical Modification. In thismethod, the lignocellulose may be esterified by, for example,acetylation, or it may be cross-linked using, for example, an aldehyde.An alternative method of Chemical Modification is to react hemicellulosewith lignin under elevated temperatures, typically using steamtreatment. These methods of chemical modification are costly and reducethe strength of the once-formed composite.

The phenol-formaldehyde resin used in the manufacture of lignocellulosiccomposite products may be in the form of a solid or a liquid. Powderedphenolic resins, such as novolac, resole, or combinations thereof, maygenerally be used. U.S. Pat. No. 4,098,770 to Berchem, et al., disclosesa spray-dried phenol-formaldehyde resin modified with added non-phenolicpolyhydroxy compounds, used in the manufacture of waferboard. Liquidphenol-formaldehyde resins, such as resole or resole and novolaccombinations, may also be used in the manufacture of lignocellulosiccomposite products. Parameters for the manufacture of either liquid orsolid phenol-formaldehyde resins are disclosed in Phenolic Resins,Chemistry, Applications and Performance, (A. Knop and I. A. Pilato,Springer-Verlag (1985)) and Advance Wood Adhesives Technology, (A Pizzi,Marcel Dekker (1994)).

Historically, molten hydrocarbon and simple emulsions utilizing stearicacid/triethanolamine (TEA) or diethanolamine (DEA) and/or lignosulfonateas surfactants have been used in the manufacture of board panels toimpact water resistance with varying degrees of performance. However,they generate undesired emissions, inconsistent performance, handlingand storage difficulties, foaming, and non-predictable applicationlevels of the wax system to achieve the results.

A method widely used in the conventional bonding process to improvedimensional stability, as noted above, is the application of a waxsizing agent. The wax sizing imparts a certain degree of waterrepellency to the once-formed composite. Paraffin is a compound sizingagent. One method by which wax sizing imparts water repellency is bycoating the surface of the lignocellulose, thus decreasing its surfacetension. Another method by which wax sizing imparts water repellency isby partially filling the capillaries within the lignocellulose, thusproviding a barrier to the capillary uptake of water.

Conventional preservatives for lignocellulosic products often containheavy metals, for example, chromated copper arsenate (CCA). Pressuretreatment of wood products, i.e., lumber, using CCA is referred to aswolmanizing. Other methods involve the use of creosote oil containingpolycyclic aromatic hydrocarbons (PAHs), referred to as creosoting. Inthese conventional methods, the preservative will often penetrate thewood only around the edges. In addition, the use of a wolmanized and/orcreosoted wood is coming under increasing pressure from environmentalgroups. Problems with CCA-treated wood include difficulty in meeting theWater Pollution Control Laws, the problem of waste wood treated with CCAor the like, at least in part due to the heavy metals present in thispreservative. While creosote oil has good permeability, weatherresistance and preservative property, it has problems such as odor, skinirritation, health damage, and a black color. Alternative preservativesystems for lumber, with lower perceived risk, such as ammoniacal copperquat (ACQ), ammonial copper zinc arsenate (ACZA), copperbis(dimethyldithiocarbamate) (CDDC), ammoniacal copper citrate andcopper azole, are also in limited commercial use.

Modern organic biocides are considered to be relatively environmentallybenign and not expected to pose the problems associated with CCA-treatedlumber, for example. Biocides such as tebuconazole are quite soluble incommon organic solvents while others such as chlorothalonil possess onlylow solubility. The solubility of organic biocides affects the marketsfor which the biocide-treated wood products are appropriate. Biocideswith good solubility can be dissolved at high concentrations in a smallamount of organic solvents, and that solution can be dispersed in waterwith appropriate emulsifiers to produce an aqueous emulsion. Theemulsion can be used in conventional pressure treatments for lumber andwood treated in such a manner can be used in products such as deckingwhere the treated wood will come into contact with humans. Biocides,which possess low solubility, are often incorporated into wood in asolution of hydrocarbon oil such as AWPA P9 Type A, and the resultingorganic solution is used to treat wood directly. Wood treated in thisway can be used only for industrial applications, such as utility polesand railway ties, because the oil is irritating to human skin.

There is a need for lignocellulosic products that are dimensionallystable when exposed to moisture. There is a further need forlignocellulosic products that do not swell when immersed in water andthat do not shrink when dried, and there is a need for applying a broadrange of preservatives and organic biocides to wood and lignocellulosiccomposite products.

SUMMARY OF THE INVENTION

In one embodiment, an emulsion described herein comprises anonsaponifiable wax, a saponified wax, an alkyl phenol component, adispersant/surfactant, a carboxymethylcellulose component, and water. Ina particular embodiment, the nonsaponifiable wax may comprise about 33%to about 35% of the emulsion, by weight, the saponified wax may compriseabout 3% to about 5% of the emulsion, by weight, the alkyl phenolcomponent may comprise about 0.5% to about 2.5% of the emulsion, byweight, the dispersant may comprise about 0.5% to about 2% of theemulsion, by weight, and the carboxymethylcellulose component maycomprise about 0.2% to about 5% of the emulsion, by weight. Optionally,the emulsions may comprise a preservative.

A method for improving the water resistance of a lignocellulosiccomposite product prepared by mixing lignocellulosic material with abinder to form a mixture and solidifying the mixture in a selectedconfiguration to form the composite product comprises adding to themixture an emulsion as described above. A lignocellulosic compositeproduct may be made by mixing lignocellulosic material with a binder toform a mixture, adding to the mixture an emulsion as described above,and solidifying the mixture in a selected configuration to form thecomposite product. A method for treating wood comprises impregnating thewood with an emulsion as described above.

A method is also provided for making an emulsion, the method comprisingcharging a single vessel with a molten nonsaponifiable wax, a moltensaponified wax, an alkyl phenol component, water, adispersant/surfactant, and a carboxymethylcellulose component to form amixture, and heating and agitating the mixture in the vessel. Themixture may then be homogenized. Preferably, the method may includeproviding saponified wax by charging the vessel with molten saponifiablewax and a saponifier.

A method is also provided for adding preservative to lignocellulosicproduct, comprising impregnating the lignocellulosic product with apreservative solution comprising the preservative and an emulsion in acarrier solvent, and removing carrier solvent from the lignocellulosicproduct. In one embodiment, impregnating the lignocellulosic productcomprises placing the lignocellulosic product in a chamber,depressurizing the chamber, adding the preservative solution to thechamber in contact with the lignocellulosic product and re-pressurizingthe chamber.

Also disclosed are lignocellulosic products resulting from said method.

BRIEF DESCRIPTION OF THE FIGURE

The sole FIGURE is a plot of the test results of sample boards preparedwith the disclosed emulsions, in relation to a commercially availablecontrol.

DETAILED DESCRIPTION OF THE INVENTION

Emulsions described herein are useful in improving the water resistanceof lignocellulosic products, thus ameliorating the detrimental effectsthat absorbed water can have on such products, including dimensionalinstability (swelling) and biological degradation. Optionally, theseemulsions may include preservatives that are not themselveswater-repellant, the emulsions serving as carriers for delivering thepreservatives into lignocellulosic products e.g., lumber, and ininhibiting the leaching of such preservatives from such productsthereafter.

The emulsions described herein result from the combination of a waxcomponent comprising a nonsaponifiable wax, a saponifiable wax, asaponifier, an alkyl phenol component, a dispersant/surfactant such as aphenate salt, a carboxymethylcellulose, and water, which are formed intoan emulsion with the wax component becoming the discontinuous phase.These wax-in-water emulsions may be added to a mixture oflignocellulosic materials, and/or other components that go into thecomposite products, without adversely affecting properties of themixture which are necessary to the manufacture of lignocellulosiccomposite products, and they may be impregnated into lumber. Methods formaking and using such emulsions, and lignocellulosic products containingsuch emulsions are also disclosed.

Examples of lignocellulosic materials from which lignocellulosiccomposite products may be made using these emulsions include, but arenot limited to, wood fiber, wood flake, wood strands, wood chips andwood particles, straw, bagasse, wood bark, recycled wood fiber, recycledpaper fiber, and mixtures thereof. The composite panels produced areknown as fiberboard, waferboard, strandboard, oriented strandboard,flakeboard, particleboard, plywood and the like. Such products may alsocontain resins such as phenol-formaldehyde (PF), urea-formaldehyde (UF),or a combination thereof, provided in the furnish from which theproducts are formed. The emulsions described herein may be mixed withsuch resins to provide a combined system for delivery to thecomposite-making process. Without wishing to be bound by any particulartheory, it is believed that in these emulsions the surfactant systemaligns with the discontinuous phase (i.e., wax phase) and may couplewith lignin fibers, providing hydrophobicity to composite products,e.g., boards, containing those fibers.

Emulsions described herein comprise a wax component comprising anonsaponifiable wax and a saponifiable wax. The nonsaponifiable wax maycomprise a wax having a melting point greater than about 120° F. (about49° C.), e.g., about 120° F. to about 165° F. (about 49° C. to about 74°C.), optionally about 120° F. to about 150° F. (about 49° C. to about66° C.), and preferably about 135° F. to about 145° F. (about 57° C. toabout 63° C.). (All ranges disclosed herein are inclusive andcombinable, e.g., ranges of “about 120° to about 165° F., optionallyfrom 135° to 145° F.”, are inclusive of the endpoints and allintermediate values of the ranges and combinations thereof, including,e.g., about 120° to about 145° F., about 130° to about 150° F., etc.)Suitable nonsaponifiable waxes include paraffin waxes, slack waxes andscale waxes. Such waxes are commercially known to be of low volatility,exhibiting less than about a 10% loss in weight during standardthermogravimetric analysis. Also, the oil content of these waxes istypically less than about 5% by weight, preferably less than about 1% byweight. Some of these waxes are of a relatively high molecular weight,having an average chain length of C₃₆, that is a 36 carbon chain length,or greater. Paraffin waxes are typically derived from light lubricatingoil distillates and are predominantly straight chain hydrocarbons havingan average chain length of 20 to 30 carbon atoms. Suitable paraffinwaxes include Wax 3816 available from Honeywell/Astor of Duluth, Ga.Slack waxes are petroleum waxes having an oil content of 3 to 50 wt %.Suitable slack waxes include Exxon 600 Slack Wax and Ashland 200 SlackWax, and a combination of 50 parts Exxon 600 Slack Wax and 50 partsAshland 200 Slack Wax.

A suitable saponifiable wax has an acid value or a saponification valueand a melting point greater than about 180° F. (about 82° C.).Saponifiable waxes include waxes from the liquefication of coal,vegetable waxes and oxidized waxes resulting from the processing and/orrefining of slack wax, scale wax or crude petroleum. For example,saponifiable waxes include montan wax, carnauba wax, beeswax,bayberry-myrtle wax, candelilla wax, caranday wax, castor bean wax,esparto grass wax, Japan wax, ouricury wax, retamo-ceri mimbi wax,shellac, spermaceti wax, sugar cane wax, wool-lanolin wax, and others.One example of a useful saponifiable wax is a montan wax having a meltpoint of about 190° to about 200° F. (about 88° to about 93° C.) meltpoint. Saponification of such waxes occurs as a result of combining thewax with a saponifier, i.e., strongly basic material such as ammoniumhydroxide or an alkali metal hydroxide such as sodium hydroxide orpotassium hydroxide. The amount of saponifier needed to saponify a waxmay be calculated based on the saponification value of the wax. Forexample, the saponification value divided by 1000 equals the grams ofpotassium hydroxide to add per gram of wax.

Preferably, the waxes do not contain more than about 5% (by weight)polar compounds as impurities.

The wax component may be present in an amount of about 25 percent byweight (wt %) to about 50 wt %, based on the total weight of theemulsion, preferably about 30 wt % to about 40 wt %. Preferably, the waxcomponent comprises a combination of a nonsaponifiable wax having amelting point of greater than or equal to about 120° F. and asaponifiable wax. The nonsaponifiable wax may comprise about 25 wt % toabout 44 wt % of the total weight of the preservative composition, andthe saponifiable wax may comprise about 0.5 wt % to about 5 wt % of thetotal weight of the emulsion. A preferred combination of waxes is acombination of a paraffin wax such as Honeywell 3816 as the first waxand a saponifiable wax such as montan wax. In one embodiment, the waxcomponent comprises paraffin wax in an amount of about 25 wt % to about45 wt %, preferably about 30 wt % to about 40 wt %, and saponifiable waxin an amount of about 2.5 wt % to about 5 wt %, preferably about 3.5 wt% to about 4.5 wt %, based on the total weight of the emulsion.

A strongly basic compound is added to the emulsion mixture to saponifythe saponifiable wax. The saponifier may comprise, e.g., ammoniumhydroxide or an alkali metal hydroxide, e.g., sodium hydroxide orpotassium hydroxide. The alkali metal hydroxide may be provided in theform of a concentrated aqueous solution that may comprise about 45%alkali metal hydroxide, by weight. Ammonium hydroxide may be provided insolid form. Some or all of the saponifier may also react with thedispersant, and/or with other component ingredients of the emulsion, insitu. Although ammonium hydroxide is sometimes objected to because ofthe ammonia odor it produces, ammonium hydroxide is believed to beadvantageous because, in addition to saponifying the wax, the ammoniacan serve as a scavenger for formaldehyde in the resin with which theemulsion is used, and may thus reduce the emission of formaldehyde fromthe finished composite product. The combination of ammonium hydroxidewith formaldehyde also ameliorates the ammonium hydroxide odor, so insome embodiments, formaldehyde may be added to the emulsion for thispurpose, for example, in an amount of about 0.02 to about 0.1% byweight. In addition, ammonium hydroxide is especially advantageous forwhen the emulsion is used with lignocellulosic materials comprisingnorthern wood species, i.e., Douglas fir, aspen and the like.

The saponifier may be provided in an amount of about 0.15% to about4.5%, optionally about 0.5% to about 3%, of the emulsion, by weight.Optionally, concentrated aqueous saponifier may be provided in an amountof about 0.5 to about 3% by weight of the emulsion; ammonium hydroxidemay be added in solid form in an amount of about 0.15 to about 3% byweight of the emulsion. The amount of saponifier may be varied with thetype of saponifiable wax used, or with the type of wood. As a result ofthe saponifier, an emulsion as described herein may have a pH of about8.5 to about 12.5, for example, a pH of about 8.5 to about 9.5.

Exemplary carboxymethylcellulose materials useful in these emulsionshave molecular carbon chain lengths of about 20 to about 50 carbons. Anexample of a suitable carboxymethylcellulose is carboxymethylcellulosesodium, available from Penn Carbose, Somerset, Pa., under the tradedesignation LT-30, which is described as having carbon chain lengths ofabout 26 to 30 carbons. Other suitable carboxymethylcellulose materialsinclude Penn Carbose LT-20 and LT-42. The carboxymethylcellulose and theproduct of its reaction with the saponifier or with any other componentin the emulsion are referred to herein as the “carboxymethylcellulosecomponent”.

A salt of polynaphthalenesulfonic acid is useful in the emulsionsdescribed herein and, without wishing to be bound by theory, is believedto act as a dispersant/surfactant. The salt may be the product of anin-situ reaction of polynaphthalenesulfonic acid and a saponifier, e.g.,an alkali metal hydroxide. One commercially availablepolynaphthalenesulfonic acid is DISAL GPS which may be obtained fromHandy Chemical, Montreal, Quebec, Canada. The acid and acid salt arereferred to collectively as a polynaphthalenesulfonic acid component or,more broadly (to include substitute materials), as thedispersant/surfactant. The dispersant/surfactant may comprise about 0.1%to about 5% of the emulsion, by weight, optionally about 0.25 wt % toabout 5 wt %.

Incorporating all alkyl phenol into the emulsions has been found tofacilitate achieving low water absorption in the final lignocellulosiccomposite product. As used herein, “alkyl phenol” refers to a phenoliccompound having a long chain alkyl group. The long chain alkyl group maybe straight or branched. The long chain alkyl group may be C₂₀-C₄₂ (from20 to 42 carbon chain length), e.g., C₂₄-C₃₄, preferably C₂₄-C₂₈. Suchalkyl phenols include polymerized methylene-coupled alkyl phenol,phenate salts, calcium phenates, long branched chain calcium alkylphenols, long straight chain calcium alkyl phenols and complex polymersof maleic acid with and without an amine group substitution. The longchain alkyl group may be a polymeric group such as a polyethylene,polypropylene, or polybutylene group, for example. The alkylsubstituents may be a mixture of different chain lengths as is often thecase with commercially available materials. Preferably, the alkyl phenolis chosen so that the average carbon chain length of the alkyl portionmatches, i.e., is approximately the same as or is close to, the averagecarbon chain length of the carboxymethylcellulose. For example, an alkylphenol of average chain length in the range of about C₂₄ to about C₃₄may be used in an emulsion comprising carboxymethylcellulose having anaverage chain length of about 26 to about 32 carbons, e.g., CarboseLT-30 carboxymethylcellulose.

The alkyl group of the alkyl phenol can be derived from a correspondingolefin; for example, a C₂₆ alkyl group is derived from a C₂₆ alkene,preferably a 1-alkene, a C₃₄ alkyl group is derived from a C₃₄alkene,and mixed length groups are derived from the corresponding mixture ofolefins. When the alkyl group is an alkyl group having at least about 30carbon atoms, however, it may be an aliphatic group (or a mixture ofsuch groups) made from homo- or interpolymers (e.g., copolymers,terpolylners) of mono- and di-olefins having 2 to 10 carbon atoms, suchas ethylene, propylene, butene-1, isobutene, butadiene, isoprene,1-hexene, and 1-octene. Aliphatic hydrocarbyl groups can also be derivedfrom halogenated (e.g., chlorinated or brominated) analogs of such homo-or interpolymers. Such groups can, however, be derived from othersources, such as monomeric high molecular weight alkenes (e.g.,1-tetracontene) and chlorinated analogs and hydrochlorinated analogsthereof, aliphatic petroleum fractions, particularly paraffin waxes andcracked and chlorinated analogs and hydrochlorinated analogs thereof,white oils, synthetic alkenes such as those produced by theZiegler-Natta process (e.g., poly(ethylene) greases) and other sourcesknown to those skilled in the art. Unsaturation in the hydrocarbylgroups can be reduced or eliminated, if desired, by hydrogenationaccording to procedures known in the art. Preparation by methods andmaterials that are substantially free from chlorine or other halogens issometimes preferred for environmental reasons.

More than one alkyl group can be present, but usually no more than 2 or3 are present for each aromatic nucleus in the aromatic group. Mosttypically only one hydrocarbyl group is present per aromatic moiety,particularly where the hydrocarbyl-substituted phenol is based on asingle benzene ring.

The alkyl phenol and product of the reaction of an alkyl phenol with asaponifier or with any other component of the emulsion is referred toherein as the alkyl phenol component.

The amount of alkyl phenol component present in the emulsion is about0.25 wt % to about 10 wt %, optionally about 0.5 wt % to about 2.5 wt %based on the total weight of the emulsion.

One example of an alkyl phenol component useful in the compositions ofthe present invention is commercially available under the tradedesignation 319H from Lubrizol Chem. Corp. Wycliffe, Ohio, whichmaterial is described as a C₂₄-C₃₄ polymerized methylene-coupled alkylphenol.

A novel method of manufacture for the emulsions described herein resultsin time, energy, operator, and production efficiencies. The methodinvolves mixing the ingredients of the emulsion in a single vessel andthen conveying the mixture of a homogenizer under conditions such as thefollowing. An advantage of this method is that the emulsion mixture isprepared in a single vessel; it is not necessary to prepare andseparately store partial mixtures of the ingredients of the emulsion inseparate vessels before combining them together.

The nonsaponifiable wax (e.g., 3816 wax, further described below) ismelted and stored in molten form, e.g., at about 10° F. above its meltpoint temperature, and water is provided at a temperature that will notcause the wax to solidify. The vessel is then charged in the followingillustrative manner:

a. Charge the melted nonsaponifiable wax, e.g., 3816 wax, at atemperature of about 189° F. to about 192° F. (about 87° C. to about 89°C.);

b. Start heat and agitation;

c. Charge molten saponifiable wax and alkyl phenol with continuedagitation;

d. Charge a majority of the water, e.g., 95%, and continue agitation;

e. Charge the dispersant/surfactant, (e.g., DISALpolynaphthalenesulfonic acid, further described elsewhere herein),carboxymethylcellulose and saponifier;

f. Charge the remaining water—preferably including the water used torinse the tubes calculated and subtracted out of the total;

g. Bring the tank up to temperature, e.g., about 190° F. to about 210°F. (about 88° C. to about 100° C.);

h. Continue to agitate while maintaining temperature for about 30 toabout 150 minutes;

i. Put through homogenizer at about 1500 to about 3500 PSI (about 10megapascals (MPa) to about 24 MPa);

j. Cool, optionally in process that provides two exotherms, including afirst exotherm between the exit temperature from the homogenizer to atemperature above ambient, and a second exothem to ambient (storage)temperature. For example, the enulsion composition is passed from thehomogenizer to a cooler to achieve a first exotherm of, e.g., about 10°F. to about 20° F. degrees lower than the homogenizer exit temperature,and then to a cooling tank to achieve a second exotherm of, e.g. aboutan additional 5° F. to about 15° F. lower, optionally under agitation.In one embodiment, the first exotherm may occur by cooling from about130° F. to about 110° F., and the second exotherm may occur by coolingfrom about 110° F. to about 70° F.

Without wishing to be bound by any particular theory, using atwo-exotherm cooling process allows a phasing process of the formationof the emulsion to proceed to completion. As a result, the viscosity ofthe emulsion is more stable over time and the emulsion is more stablewhen subject to shear agitation than if a single exotherm coolingprocess is used. In an alternative method of preparing the emulsion, abatch process may be used in which a first premix comprising the moltenwaxes and alkylphenol may be prepared, and a second premix (an aqueouspremix) comprising the water, carboxymethylcellulose andpolynaphthalenesulfonic acid and saponifier may be prepared, and thefirst and second premixes may then be combined in a mixing tank for atime sufficient at least for the waxes to become saponified, e.g., forone to three hours, and the resulting mix may then be passed to ahomogenizer and cooled as described above.

Illustrative ranges of ingredients in some embodiments of emulsionsdescribed herein are provided in Table 1 below. TABLE 1 ILLUSTRATIVEEMBODIMENTS Component Typical Amount (% weight basis) NonsaponifiableWax 33-35 Saponifiable Wax 3-5 Alkyl Phenol 0.5-2.5Polynaphthalenesulfonic Acid 0.5-2   Carboxymethylcellulose 0.2-5  Saponifier Amount used depends on amount of saponifiable wax; typically0.5-3 Water Balance (to 100)

Table 2 provides example proportions of ingredients in a specificembodiment of an emulsion as described herein. TABLE 2 ILLUSTRATIVEEMULSION INCLUDING POLYNAPHTHALENESULFONIC ACID Component Weight % Wax3816 33.00 Saponifiable Wax 3.00 Alkyl Phenol 0.50Polynaphthalenesulfonic Acid (DISAL GPS) 0.50 Carboxymethylcellulose 0.245% KOH (saponifier) 0.75 Water Balance (to 100)

The emulsions described herein may include optional additionalingredients to enhance their performance during the manufacture of thelignocellulosic composite products and the performance of the resultingcomposite products. An emulsion as described herein may have a viscosityof about 10 to about 100 centipoise, measured on a Brookfieldviscometer. One sample emulsion had a viscosity of 9 cps at about 40%solids. The stability and shear performance and lack of foam generationfurther enhance the ability to receive these emulsions. For example, onesample emulsion remained intact even after four minutes agitation in afood blender. These emulsions are also compatible with urea-formaldehydeand phenol-formaldehyde resin systems used in the manufacture of manylignocellulosic products. Further, this system is amphoteric and wouldtherefore be stable over a wide pH range, and becomes a part of thetotal process rather than additive to the process, thus providing a moreuniform finished product. Embodiments of these emulsions have beendemonstrated not to contribute to biological activity.

Oriented strand board (OSB) is one type of composite that can bemanufactured using an emulsion as described herein. To produce OSB usingthe hot press method, lignocellulosic material is combined with a resinand the emulsion of the present invention in a mixer. The resultingpre-form mixture is flowed onto a support material to make a pre-formfor 7/16 inch (about 1.1 centimeters (cm))- and ⅝ inch (about 1.6cm)-thick oriented strand board. The pre-form is then placed on a caulplate in a hot press where the finished good is produced by applyingpressures above atmospheric and temperatures greater than roomtemperature. The hot press method is further described in U.S. Pat. No.4,433,120 to Shui-Tung Chiu. Twelve inch by twelve inch (30.5 cm×30.5cm) panels can be cut from the finished good and tested for density,swell and absorption. Optionally, the pre-form mixture may include apreservative mentioned below to inhibit unwanted biological growth inthe panels.

To illustrate the water-resistance imparted by emulsions describedherein, several samples of oriented strand board (OSB) were preparedwith varying amounts of an emulsion. Sample OSB boards were preparedfrom mixtures of wood strands, flakes or wafers with a resin binder andan emulsion as described in Table 2 in amounts ranging from about 1% toabout 0.25% on a volume basis of the resin in the mixture (“vol. %”).The mixtures were placed in a mold and cured to yield boards. Acomparison board was prepared using 1 vol. % of a commercially availablecomparative emulsion known as Cascowax EW-58, which is believed tocomprise a stearic acid TEA emulsion have a solids content of about 58%.Samples were cut from the boards, were measured and weighed and werethen immersed in water at about room temperature (e.g., about 72° F.(about 22° C.)) for 24 hours, after which they were again measured andweighed.

The following Table 3 shows the various charges of sample emulsions, thecontrol, and the results of water absorption, edge swell and thicknessswell test results from tests performed. Water absorption was measuredas the increase in weight of a sample relative to the starting weight.Edge swell is a measure of the average increase in the thickness of thesample measured along one or more edges, relative to the startingthickness, and center swell is a measure of the increase in thickness ofthe sample at the center, relative to the starting thickness. TABLE 3Twenty-Four-hour water absorption (WA) and Thickness Swell Results Vol %% Edge % Center Density Sample emulsion % WA swell swell (pcf) Control1.0%  73.09 40.04 36.03 44.3 Sample 1 1.0%* 50.34 22.53 22.32 41.9Sample 2 0.75%*  54.18 28.61 18.91 43.7 Sample 3 0.5%* 52.29 25.09 21.5441.8 Sample 4 0.25%*  84.92 37.57 29.47 40.1*% volume basis in resin wood (OSB) (oriented strand board)

The data of Table 3 show that the sample emulsion provides significantlyimproved performance in both water uptake and edge and center swell inwood composite products. Specifically, Samples 1-3 had lower waterabsorption, edge thickness swell, and center swell than the control, andwere all similar to each other, even though samples 2 and 3 containedsignificantly less emulsion than the control. The data shows thatimproved performance is achieved at reduced rates on a volume/volumebasis relative to the control, i.e., approximately 50-75% less emulsionversus the control. The test emulsions release fewer emissions from OSBand other board products, cause less board/resin interference, and theyare less sensitive to storage condition requirements than certain otheremulsions. Application was on an equal liquid application, thereforelower solids applied for all wax conditions. To be noted is the slightlyhigher density of the emulsion wax sample. The reduction in emissions isdue, at least in part, to the fact that results comparable to thecontrol may be attained with a charge of emulsions that introduceslesser quantities of materials into the lignocellulosic product. Forexample, Table 3 shows that better results were obtained with 1% of thesample emulsion, which contains only about 40% solids, than with 1% ofthe control, which contained about 60% solids. Another factor that maycontribute to a reduction in emissions is that the described emulsionscomprise higher melting waxes, which contain smaller volatile fractionsthan lower-melting waxes.

Embodiments of the described emulsions that contain ammonium, e.g., froman ammonium hydroxide saponifier, exhibit superior performance relativeto other embodiments. This was demonstrated by preparing a series ofemulsions all of which made with the following: 33% nonsaponifiable wax;3% montan wax, 0.5% alkylphenol; 2% polynaphthalenesulfonic acid (or,where noted 2.5%); 0.5% carboxymethylcellulose. The embodiments weremade with the indicated quantity of saponifier, the nonsaponifiablewaxes and with additional components in the amount set forth in thefollowing Table 4, with water comprising the balance. The samples ofTable 4 were prepared using the batch process described above. Inemulsions B and E, the indicated formaldehyde was included in theaqueous premix; in emulsions C, F, G, H, and I, the indicatedformaldehyde was added to the emulsion after the emulsion was formedfrom the other components. TABLE 4 Nonsaponifiable Emulsion Ammoniumhydroxide formaldehyde wax A 0.38% 0.0 3816 B 0.38% 0.25 3816 C 0.38%0.25 3816 D 0.45% 0.0 3816 E 0.45% 0.25 3816 F 0.45% 0.25 3816 G^(i)0.45% 0.25 3816 H 0.45% 0.25 Prowax^(ii) 561 I 0.45% 0.25 Prowax^(ii)321 J 0.45% 0.0 3816^(i)Emulsion G contained 2.5% polynaphthalenesulfonic acid^(ii)Prowax 561 and 321 are hard paraffin waxes commercially availablefrom ExxonMobil Corporation

Samples of oriented strand board (OSB) were prepared using emulsionsA-J. In addition, a sample OSB was prepared using an emulsion as setforth in Table 2 above (designated sample ‘K’ in the FIGURE), andanother sample (whose performance is represented by the base line 0%)was made using a commercially available Cascowax emulsion sold under thecommercial designation EW-50S, which is believed to be a paraffin waxemulsion with stearic acid and TEA (triethanolamine). The samples weretested for water absorption, edge swell and center swell as describedabove. The results are set forth in the accompanying FIGURE, in whichthe reduction in water absorbance (bars WA), edge swell (bars ES) andcenter swell (bars CS) of each of the other samples is shown in theFIGURE as a degree of improvement (% Δ) relative to the baseline sample.The results shown in the FIGURE indicate that all of the sampleemulsions performed better than the EW-50S in at least two of the threetests.

The experimental results demonstrate that the emulsions described hereinprovide superior performance with regard to imparting water resistancein lignocellulosic products, and so eliminates the need for lignincompounds and biocides in some of those products. The elimination ofthese latter two compounds improves the manufacture and lowers cost ofthe lignocellulosic composite products and wood using these emulsions.

The emulsions described herein can be incorporated into lumber or otherlignocellulosic products to help resist the absorption of water. Thesubsequent drying of the lignocellulosic product is believed to breakthe emulsion, which releases the waxes therein and allows the waxes tomigrate to the surface of the product, thus enhancing thewater-resistance characteristics. Optionally, the emulsions describedherein can be adjuvants for impregnating preservatives intolignocellulosic composite products or into wood in amounts effective toinhibit a biological activity, i.e., biological degradation, such as thegrowth of molds, fingi, bacteria, insects, etc. Used in this way, theemulsions help the lignocellulosic material retain the preservatives andreduces the amount of preservatives that leach into the environment whenthe preserved product is placed in use.

To evaluate the ability of emulsions described herein to help retainabsorbed preservatives in lumber or other lignocellulosic products andto prevent the leaching of preservatives therefrom, a copper-basedpreservative (ACQ) was impregnated into wood samples with a sampleemulsion and a comparative emulsion, and the preserved wood samples werethen immersed in water and the tendency of the copper to leach out wasobserved, as follows.

A preservative solution is prepared by combining 25% of a 40% solutionof ACQ with 70% water and 5% of a sample emulsion as described in Table2. The resulting mixture was stirred at room temperature for 2 minutes.The copper concentration in this starting mixture was measured using DSC(differential scanning calorimetry) methods known in the art. Acomparative solution was prepared using a comparative stearic acid andtriethanolamine composition that is commercially available from Osmose,of Griffin, Ga., USA or Arch-Wood Protection Incorporated of Smyrna,Ga., USA.

Sanded pine wood lath strip specimens measuring 2 inch×¼ inch×12 inchesin length were placed in the wood preservative solution for 2 minuteswith vigorous stirring, and were then withdrawn. The amount of copperretained in the solution after each specimen was withdrawn was againmeasured, and the difference from the starting solution indicated theamount of copper impregnated into the wood specimen.

The specimens were allowed to drip dry for 2 minutes, and were thendried for 24 hours in an oven controlled to 70 degrees F. After drying,each treated wood specimen was immersed in clean water with vigorousstirring for 2 minutes. The quantity of copper in the water was thendetermined using DSC techniques, and the difference between the amountof copper in the water and the amount absorbed by the specimen was theamount retained by the specimen; the relative amount of copper in thewater indicated the degree of leaching.

Results: From the specimens impregnated with a preservative solutioncomprising the comparative emulsion, about 100% of the impregnatedcopper leached out, whereas from the specimens impregnated with thepreservative solution comprising the sample emulsion, only 15% to about25% of the impregnated copper leached out. These results show thesuperiority of the sample emulsions described herein for carryingpreservatives into wood and preventing the leaching of the preservativesfrom the wood thereafter.

Commonly, lumber comprises wood that has been impregnated with apreservative in a process that employs a preservative solutioncomprising the preservative in a carrier solvent (typically water). Themethod involves placing the wood in a vacuum chamber, evacuating thechamber, introducing a preservative solution into the chamber in contactwith the lumber, pressurizing the chamber to facilitate absorption ofthe preservative solution by the wood, and then depressurizing thechamber to withdraw carrier solvent from the wood. The preservative iscarried into the wood during absorption, and at least a portion of thepreservative remains in the wood after carrier solvent is removed. Theemulsions described herein can be added to the preservative solution tofacilitate absorption of the preservatives by the wood and the retentionof the preservatives therein when carrier solvent is subsequentlyremoved.

Suitable preservatives that may be incorporated into lignocellulosicproducts with an emulsion described herein may be inorganic or organic,and include, for example biocides such as insecticides, fungicides,bactericides, and combinations comprising one or more of the foregoingbiocides. The biocide may be chosen according to (1) the targetorganism; (2) solubility characteristics; (3) stability to thetemperature and pH; and other conditions found in the manufacture of thecomposites. Biocides include substances that kill or inhibit the growthof microorganisms such as molds, slimes, fungi, bacteria, etc.Insecticides, fungicides and bactericides are all examples of biocides.Fungicides include substances that kill or inhibit the growth of fungi.Bactericides include agents that kill bacteria. Insecticides are agentsthat kill insects. More specific examples of biocides include, but arenot limited to, chlorinated hydrocarbons, organometallics,halogen-releasing compounds, metallic salts, organic sulfur compounds,and phenolics. Preferred biocides include but are not limited tochromated copper arsenate (CCA); such as ammoniacal copper quaternaryammonium (ACQ), ammonial copper zinc arsenate (ACZA), copperbis(dimethyldithiocarbamate) (CDDC), ammoniacal copper citrate andcopper azole, copper naphthenate, zinc naphthenate, quaternary ammoniumsalts, pentachlorophenol, tebuconazole (TEB), chlorothalonil (CTL),chlorpyrifos, isothiazolones, propiconazole, other triazoles,pyrethroids, and other insecticides, imidichloprid, oxine copper and thelike, and combinations comprising one or more of the foregoing biocides.In addition to the organic biocides, nanoparticles with variable releaserates that incorporate such inorganic preservatives as boric acid,sodium borate salts, zinc, zinc borate, silicated borate, copper saltsand zinc salts may be used.

Suitable general microbicides include, for example, 3-isothiazolones,3-iodo-2-propynylbutylcarbamate, 1,2-dibromo-2,4-dicyanobutane,methylene-bis-thio-cyanate (T), 2-thiocyano-methylthiobenzothiazole,tetrachloroisophthalonitrile, 5-bromo-S-nitro-1,3-dioxane,2-bromo-2-nitropropane-1,3-iol, 2,2-di-bromo-3-nitrilopropionamide(DBNPA), N,N′-dimethylhydroxyl-5,5′-dimethyl-hydantoin,bromochlorodimethylhydantoin, 1,2-benzisothiazolin-3-one,4,5-tri-methylene-2-methyl-3-isothiazolone,5-chloro-2-(2,4-dichlorophenoxy)-phenol, 3,4,4′-trichlorocarbanilide,copper naphthenate, copper-8-hydroxy-quinoline, zinc borate, boric acid,trimethyl boron, zinc oxide, glutaraldehyde,1,4-bis(bromo-acetoxy)-2-butene,4,5-dichloro-1,1-dithiacyclopentene-3-one, chlorothalonil, quaternaryammonium based compounds, and combinations comprising one or more of theforegoing microbicides.

Suitable fungicides include, for example, zinc dimethyl dithiocarbamate,2-methyl-4-t-butylamino-6-cyclopropylamino-s-triazine,2,4,5,6-tetrachloroisophthalonitrile, N,N-dimethyl dichlorophenyl urea,copper thiocyanate, N-(fluorodichloromethylthio)phthalimide,N,N-dimethyl-N′-phenyl-N-fluorodichloromethylthiosulfamide; copper,sodium and zinc salts of 2-pyridinethiol-1-oxide; tetramethylthiuramdisulfide, 2,4,6-trichlorophenyl-maleimide,2,3,5,6-tetrachloro-4-(methylsulfonyl)-pyridine, diiodomethyl p-tolylsulfone, phenyl (bispyridil) bismuth dichloride,2-(4-thiazolyl)-benzimidazole, pyridine triphenyl borane, phenylamides,halopropargyl compounds, propiconazole, cyproconazole, tebuconazole and2-haloalkoxyaryl-3-isothiazolones (such as2-(4-trifluoromethoxyphenyl)-3-isothiazolone,2-(4-trifluoromethoxy-phenyl)-5-chloro-3-isothiazolone,2-(4-trifluoromethoxyphenyl)-4,5-dichloro-3-isothiazolone), andcombinations comprising one or more of the foregoing fungicides.

The fungicide may be an agricultural fungicide such as, for example,dithiocarbamate and derivatives such as ferbam, ziram, maneb (manganeseethylenebisdithio-carbamate), mancozeb, zineb (zincethylenebisdithiocarbamate), propineb, metham, thiram, the complex ofzineb and polyethylene thiuram disulfide, dazomet, and mixtures of thesewith copper salts; nitrophenol derivatives such as dinocap, binapacryland 2-sec-butyl-4,6-dinitrophenyl isopropyl carbonate; heterocyclicstructures such as captan folpet, glyodine, dithianon, thioquinox,benomyl, thiabendazole, vinolozolin, iprodione, procymidone,triadimenol, triadimefon, bitertanol, fluoroimide, triarimol,cycloheximide, ethirimol, dodemorph, dimethomorph, thifluzamide andquinomethionate; miscellaneous halogenated fungicides such as:chloranil, dichlone, chloroneb, tricamba, dichloran andpolychloronitrobenzenes; fungicidal antibiotics such as: griseofulvin,kasugamycin and streptomycin; miscellaneous fungicides such as diphenylsulfone, dodine, methoxyl, 1-thiocyano-2,4-dinitrobenzene,1-phenyl-thiosemicarbazide, thiophanate-methyl and cymoxanil;acylalanines such as furalaxyl, cyprofuram, ofurace, benalaxyl, andoxadixyl; fluazinam, flumetover, phenylbenzamide derivatives such asthose disclosed in EP 578,586-A, amino acid derivatives such as valinederivatives disclosed in EP 550,788-A, methoxyacrylates such as methyl(E)-2-(2-(6-(2-cyanophenoxy)pyrimidin-4-yloxy)phenyl)-3-methoxyacrylate,benzo(1,2,3)thiadiazole-7-carbothioic acid S-methyl ester, propamocarb,imazalil, carbendazim, myclobutanil, fenbu-conazole, tridemorph,pyrazophos, fenarimol, fenpiclonil, pyrimethanil, and combinationscomprising one or more of the foregoing fungicides.

Combination bactericides/fungicides can be included in the preservativecompositions. An example of a bactericide/fungicide is METASOL D3TA,which is 3,5-dimethyl-tetrahydro-1,3,5,2H-thiadiazine-2-thione availablefrom Ondo-Nalco, Houston, Tex.

Suitable insecticides include, for example, acephate, aldicarb,α-cypermethrin, azinphos-methyl, bifenthrin, binapacryl, buprofezin,carbaryl, carbofuran, cartap, chlorpyrifos, chlorpyrifos methyl,clofentezine, cyfluthrin, cyhexatin, cypermethrin, cyphenothrin,deltamethrin, demeton, demeton-S-methyl, demeton-O-methyl, demeton-S,demeton-S-methyl sulfoxide, demephion-O, demephion-S, dialifor,diazinon, dicofol, dicrotophos, diflubenzuron, dimethoate, dinocap,endosulfan, endothion, esfenvalerate, ethiofencarb, ethion,ethoate-methyl, ethoprop, etrimfos, fenamiphos, fenazaflor,fenbutatin-oxide, fenitrothion, fenoxycarb, fensulfothion, fenthion,fenvalerate, flucycloxuron, flufenoxuron, fluvalinate, fonofos,fosmethilan, furathiocarb, hexythiazox, isazophos, isofenphos,isoxathion, methamidophos, methidathion, methiocarb, methomyl, methylparathion, mevinphos, mexacarbate, monocrotophos, nicotine, omethoate,oxamyl, parathion, permethrin, phorate, phosalone, phosmet,phosphamidon, pirimicarb, pirimiphos-ethyl, profenofos, promecarb,propargite, pyridaben, resmethrin, rotenone, tebufenozide, temephos,TEPP, terbufos, thiodicarb, tolclofos-methyl, triazamate, triazophos,vamidothion, and combinations comprising one or more of the foregoinginsecticides.

Antitermite agents may be used in addition to other insecticides as longas they do not detract from the properties of the other insecticides.Antitermite agents include Permetorin, Imidachlopride, Etpfenplox, andcombinations comprising one or more of the foregoing agents.

Specific examples of suitable preservatives include alkylammoniumcompounds such as didecyldimethylammonium chloride (DDAC), BARDAP(N,N-didecyl-N-methylpolyoxyethylammonium propionate), copperbenzalconium chloride or N-alkylbenzyldimethylammonium chloride (BKC);metal salts of naphthetic acid such as copper naphthenate (NCU) or zincnaphthenate (NZN); metal salts of versatic acid such as zinc versatate;triazole type compounds such as Cyproconazole[(2RS,3RS;2RS,3SR)-2-(4-chlorophenyl)-3-(cyclopropyl-1-(1H-1,2,4-triazol-1-yl)butan-2-01],Tebuconazole[(RS)-1-p-chlorophenyl-4,4-dimethyl-3-(1H-1,2,4-triazol-1-ylmethyl)pentan-3-01],Propiconazole[1-[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxoran-2-ylmethyl]-1H-1,2,4-triazole],1-[2-(2′,4-dichlorophenyl-1,3-dioxoran-2-ylmethyl]-1H-1,2,4-triazol-1-ethanolor1-[2-(2′,4′-dichlorophenyl)-4-propyl-1,3-dioxoran-2-ylmethyl]-1H-1,2,4-triazol-1-ethanol;and organic iodine compounds such asIF-1000[4-chlorophenyl-3-iodopropargyl formal], IPBC[3-iodo-2-propynyl-N-butylcarbamate], and combinations comprising one ormore of the foregoing preservatives.

The lignocellulosic preservatives may be used in combination. Preferredcombinations include Cyproconazole and DDAC; Cyproconazole and BARDAP;Tebuconazole and Propiconazole; and the like.

A compound which is effective to inhibit or prevent growth of wood rotsoil bacteria and wood soft rot fingi, mainly wood soft rot fungi suchas chaetomium globosum, may also be used as a preservative. Suchcompounds include p-cumylphenol (PCP), and its salts such as the sodiumsalt of p-cumylphenol, the ethylamine salt of p-cumylphenol, andcombinations comprising one or more of the foregoing wood preservatives.PCP inhibits the growth of wood rot soil bacteria, ascomycetes andinperfect fungi, and it is effective as an antimold agent andantitermite agent. Therefore, PCP is particularly preferable. PCP canexhibit a sufficient effect to wood materials in the treatment amount(application amount) of about 200-1,000 grams per cubic meter of wood(g/m³).

The emulsions described herein may also contain general additives forwood preservatives. For example, petroleum resins, rosins and waxes canreinforce microbicidal activity of preservatives such as PCP and impartsustainability, and therefore are suitable additional additives.

Dinitrophenol, dinitro-o-cresol, chloronitrophenol and the like known asphenol type microbicides of woods do not have antimicrobicidal activityto ascomycetes, and are therefore not included in the wood preservativesof this disclosure.

Mixtures comprising one or more of the foregoing preservatives may alsobe used. One or more preservatives may be employed in amounts effectiveto inhibit biological activity in wood or in the lignocellulosiccomposite product in which it is disposed, e.g., in amounts of about0.02 wt % to about 1 wt % of an emulsion, preferably about 0.1 wt % toabout 1 wt % of an emulsion; such amounts generally result in about 2 toabout 120 grams per cubic foot of wood (g/ft³) (about 70 to about 4240grams per cubic meter (g/m³)) and about 12 to about 120 g/ft³ (about 425to about 4240 g/m³). For example, the preservative may be present in anamount that imparts about 0.031 pounds of preservative per cubic foot(about 500 g/m³) of wood.

In addition to the lignocellulosic preservatives, it may be desirable toadd other additives to the preservative compositions. For example, itmay be desirable to treat wood and wood products with fire retardingchemicals such as borax/boric acid, guanylurea phosphate-boric acid,dicyandiamide phosphoric acid formaldehyde,diethyl-N,N-bis(2-hydroxyethyl)-aminomethyl phosphate, and combinationscomprising one or more of the foregoing additives. These fire retardantsare readily incorporated into nanoparticles formed, for example, frompolyvinylpyridine or polyvinylchloride. Other additives that are conferdesirable characteristics on wood and wood products and which may beadded to the compositions are water repellants, colorants, UVinhibitors, adhesive catalysts, and combinations comprising one or moreof the foregoing additives.

There has been disclosed emulsions and lignocellulosic compositeproducts made using such an emulsion. These emulsions are usefull inimparting water-resistance to the lignocellulosic composite products anddo not contribute to biological activity in the products. In someembodiments, these emulsions may be added to hot, even boiling, waterwithout the emulsion separating or curdling, they may be stable forextended periods of time when stored at room temperature, they may notrequire the addition of a bactericide, and/or they may be pourableliquids at room temperature. Optionally, these emulsions may containpreservatives. While certain embodiments and best mode are describedherein, these embodiments are merely illustrative. It will be apparentto those skilled in the art that modifications may be made thereinwithout departing from the spirit and the scope of the appended claims.

1. An emulsion comprising: a wax component comprising a nonsaponifiablewax and a saponified wax; an alkyl phenol component; adispersant/surfactant; a carboxymethylcellulose component; and water. 2.The emulsion of claim 1 wherein the wax component comprises about 25% toabout 50% of the emulsion, by weight.
 3. The emulsion of claim 6 whereinthe wax component comprises about 30% to about 40% of the emulsion, byweight.
 4. The emulsion of claim 1 wherein the nonsaponifiable wax is aslack wax, a scale wax, a paraffin wax or a combination thereof.
 5. Theemulsion of claim 1 wherein the saponified wax is produced by reactionof a saponifiable wax with ammonium hydroxide, an alkali metal hydroxideor a combination thereof.
 6. The emulsion of claim 5 comprising asaponified wax produced by reaction of a saponifiable wax with potassiumhydroxide or sodium hydroxide.
 7. The emulsion of claim 5 comprising asaponified wax produced by reaction of a saponifiable wax with ammoniumhydroxide.
 8. The emulsion of claim 1 wherein the alkyl phenol componentcomprises a C₂₀-C₄₂ alkyl group.
 9. The emulsion of claim 1 wherein thealkyl phenol component comprises a C₂₄-C₃₄ alkyl group.
 10. The emulsionof claim 1 wherein the alkyl phenol component comprises a C₂₄-C₂₈ alkylgroup.
 11. The emulsion of claim 1 wherein the dispersant/surfactantcomprises a polynaphthalenesulfonic salt.
 12. The emulsion of claim 1wherein the alkyl phenol component comprises an alkyl phenol having analkyl group that has an average carbon chain length that matches thecarbon chain length of the carboxymethylcellulose.
 13. The emulsion ofclaim 1, wherein the nonsaponifiable wax comprises about 33% to about35% of the emulsion, by weight; the saponified wax comprises about 3% toabout 5% of the emulsion, by weight; the alkyl phenol componentcomprises about 0.5% to about 2.5% of the emulsion, by weight; thedispersant/surfactant comprises about 0.5% to about 2% of the emulsion,by weight; and the carboxymethylcellulose component comprises about 0.2%to about 5% of the emulsion, by weight.
 14. The emulsion of claim 13wherein the saponified wax is produced by a reaction of a saponifiablewax with ammonium hydroxide, and further comprising about 0.5%formaldehyde, by weight.
 15. A method for improving the water resistanceof a lignocellulosic composite product prepared by mixinglignocellulosic material with a binder to form a mixture and solidifyingthe mixture in a selected configuration to form the composite product,the method comprising adding to the mixture an emulsion as defined inclaim
 1. 16. The method of claim 15 wherein the binder comprises aphenolic resin, the method comprising adding about 1% of the emulsionbased on the volume of the resin.
 17. A method for improving the waterresistance of a lignocellulosic composite product prepared by mixinglignocellusic material with a binder to form a mixture and solidifyingthe mixture in a selected configuration to form the composite product,the method comprising adding to the mixture an emulsion as defined inclaim
 13. 18. The method of claim 17 wherein the binder comprises aphenolic resin, the method comprising adding about 1% of the emulsionbased on the volume of the resin.
 19. A lignocellulosic compositeproduct made by mixing lignocellulosic material with a binder to form amixture, adding to the mixture an emulsion comprising a wax componentcomprising a nonsaponifiable wax and a saponified wax, an alkyl phenolcomponent, a dispersant/surfactant, a carboxymethylcellulose component,and water, and solidifying the mixture in a selected configuration toform the composite product.
 20. The lignocellulosic product of claim 20wherein the nonsaponifiable wax comprises about 33% to about 35% of theemulsion, by weight, the saponified wax comprises about 3% to about 5%of the emulsion, by weight, the alkyl phenol component comprises about0.5% to about 2.5% of the emulsion, by weight, the dispersant/surfactantcomprises about 0.5% to about 2% of the emulsion, by weight, and thecarboxymethylcellulose component comprises about 0.2% to about 5% of theemulsion, by weight.
 21. A method for treating wood, comprisingimpregnating the wood with an emulsion comprising a wax componentcomprising a nonsaponifiable wax and a saponified wax, an alkyl phenolcomponent, a dispersant/surfactant, a carboxymethylcellulose component,and water.
 22. The method of claim 21 wherein the wood is a northernspecies wood and wherein the emulsion comprises a saponified waxproduced by the reaction of a saponifiable wax with ammonium hydroxide.23. The method of claim 21 wherein the nonsaponifiable wax comprisesabout 33% to about 35% of the emulsion, by weight, the saponified waxcomprises about 3% to about 5% of the emulsion, by weight, the alkylphenol component comprises about 0.5% to about 2.5% of the emulsion, byweight, the dispersant/surfactant comprises about 0.5% to about 2% ofthe emulsion, by weight, and the carboxymethylcellulose componentcomprises about 0.2% to about 5% of the emulsion, by weight.
 24. Themethod of claim 23 wherein the wood is a northern species wood andwherein the emulsion comprises a saponified wax produced by the reactionof a saponifiable wax with ammonium hydroxide.
 25. The method of claim21 comprising impregnating the wood with a preservative solutioncomprising a preservative and said emulsion in a carrier solvent, andremoving carrier solvent from the lignocellulosic product.
 26. Themethod of claim 25 wherein impregnating the wood comprises placing thewood in a chamber, depressurizing the chamber, adding the preservativesolution to the chamber in contact with the wood and re-pressurizing thechamber.
 27. The method of claim 25 wherein removing carrier solventcomprises depressurizing the chamber.
 28. The method of claim 25 whereinthe preservative solution contains about 1% to about 5% emulsion byweight.
 29. The method of claim 28 wherein the preservative solutioncontains about 1% to about 2% emulsion by weight.
 30. The method ofclaim 28 wherein the preservative comprises a copper compound.
 31. Themethod of claim 30 wherein the preservative comprises ACQ.
 32. Lumbercomprising the wood treated according to the method of claim
 25. 33. Amethod for making an emulsion, the method comprising: charging a singlevessel with a molten nonsaponifiable wax, a saponifiable wax, alkylphenol, water, dispersant/surfactant, a saponifier andcarboxymethylcellulose to form a mixture; and heating, agitating andhomogenizing the mixture.
 34. The method of claim 33 comprising chargingthe vessel with the molten nonsaponifiable wax, saponifiable wax, alkylphenol component and water to form a first mixture; agitating the firstmixture; adding dispersant/surfactant, saponifier andcarboxymethylcellulose to form a second mixture, and heating, agitatingand homogenizing the second mixture.
 35. The method of claim 33 furthercomprising cooling the emulsion to ambient temperature.
 36. The methodof claim 35 comprising cooling the emulsion in a process that providestwo exotherms.
 37. The method of claim 33 comprising charging thesaponifiable wax in a quantity that comprises about 33% to about 35% ofthe emulsion, by weight; comprising charging the saponifier in aquantity that comprises about 0.5% to about 1.5% of the emulsion, byweight; comprising charging the alkyl phenol component in a quantitythat comprises about 0.5% to about 2.5% of the emulsion, by weight;comprising charging the dispersant/surfactant in a quantity thatcomprises about 0.5% to about 2% of the emulsion, by weight; andcomprising charging the carboxymethylcellulose in a quantity thatcomprises about 0.2% to about 5% of the emulsion, by weight.
 38. Themethod of claim 37 further comprising cooling the emulsion to ambienttemperature.
 39. The method of claim 38 comprising cooling the emulsionin a process that provides two exotherms.
 40. The method of claim 33comprising matching the carbon chain length of the alkyl phenolcomponent to the carbon chain length of the carboxymethylcellulose.